Watch Novak Djokovic fire a serve at Stephen Colbert

U.S. Open winner Novak Djokovic is making the media rounds after his 10th major victory, and that included a stop on The Late Show with Stephen Colbert on Monday night.

The pair chatted for a little while and then things got dangerous as Djokovic fired a serve at the host while he hid behind a Captian America shield, which Colbert says is a time-honored tradition dating to Ed Sullivan and Rod Laver.

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